In the diagnosis and monitoring of diseases, medical tests are often performed on blood, tissue, or other media sampled from patients. In a typical scenario, a doctor requests that a particular test be performed, and a sample is taken from the patient. The sample is sent to an on-site or off-site testing lab, and the results of the test are returned to the doctor for review and reporting to the patient. The test results are also typically placed in the patient's file.
Some conditions require ongoing monitoring. In these cases, tests may be performed multiple times for a particular patient.